half-life
- Noun. (physics) The time required for half of the nuclei in a sample of a specific isotope to undergo radioactive decay.
- Noun. (chemistry) In a chemical reaction, the time required for the concentration of a reactant to fall from a chosen value to half that value.
- Noun. (medicine) The time it takes for a substance (drug, radioactive nuclide, or other) to lose half of its pharmacological, physiologic, or radiological activity.
- Noun. The time it takes for an idea or a fashion to lose half of its influential power.
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This entry was last updated on RefTopia from its source on 3/20/2012.